In a majority of known coupling devices for pressurized fluid conduits, the conduits must first be depressurized before the interacting coupling members can be joined together or separated as a free outflow of medium under pressure always entails unnecessary waste and usually leads to complications in handling said coupling members. At high pressures, the risk for personal injury can also arise occasionally if the conduits are not depressurized. Furthermore, environmental damages can arise in the handling of liquid media.
Considerable risks for personal injury also exist for the known kind of so-called quick coupling intended for pressurized fluid conduits, said quick coupling comprising a casing part and a nipple part. Both are provided with a flow-through channel. The nipple part is designed to be inserted into the casing part flow-through channel in order to open a spring-loaded shut-off valve situated in the latter, thereby opening a flow-through path through the coupling and holding the valve and flow-through path open connecting the two parts to each other. For said latter purpose, the nipple part is releasably engaged in a ball locking device or similar locking device situated in the casing part. The shut-off valve situated inside the flow-through channel of the casing part comprises two interacting valve parts, both of which are axially movable relative each other and the channel under the influence of the nipple part. This is especially true when it comes to the separation of such quick coupling devices used in pressurized air conduits in which one or more hose sections are included and separation takes place without the conduit having been depressurized in advance. The brief thrust of pressure produced by the small amount of outflowing fluid has shown itself to be sufficient to occasionally cause such powerful tossing movements of the released hose ends that persons struck by said ends have even suffered disabling spinal damage.